Feline Tick Paralysis Study Guide

Overview and Clinical Importance

Tick paralysis is an acute, progressive, ascending lower motor neuron (LMN) paralysis caused by neurotoxins in tick saliva during blood feeding. While primarily a concern in Australia where Ixodes holocyclus (Australian paralysis tick) causes severe and potentially fatal disease in cats, the condition is rarely reported in feline patients in North America and Europe. Understanding the geographic differences in tick species, toxin mechanisms, and clinical presentations is essential for the NAVLE.

Tick paralysis represents a unique neurological emergency because the paralysis is chemically induced rather than infectious. The toxin prevents presynaptic acetylcholine release at the neuromuscular junction, resulting in flaccid paralysis. Without treatment, respiratory failure and death can occur within 24-48 hours of clinical sign onset.

Etiology and Pathophysiology

Causative Tick Species by Geographic Region

Toxin Mechanism: Holocyclotoxin

The primary neurotoxin responsible for tick paralysis from I. holocyclus is holocyclotoxin, a 5-6 kDa cystine knot neurotoxin. This toxin acts at the presynaptic motor nerve terminal of the neuromuscular junction.